The main goal of this project is the understanding of host defense mechanisms involved in recovery from virus-induced leukemia in mice. Individual mouse genes have been identified which appear to influence T cell-mediated or humoral virus-specific responses and the interactions of these mechanisms have been studied. Monoclonal antibodies specific for various viral proteins have also been selected and the biological roles of antibodies of different specificities and Ig classes are being studied both in in vivo and in vitro.